After transporting all the bottles, we got 1800 yuan, but the driver only got 1250 yuan, and 50 yuan for each broken bottle.
Assuming that all 360 instruments have arrived and are in good condition, the damaged instruments are:
(360×5- 1250)÷(5+50),
=550÷55,
= 10 (piece),
Answer: 10 instrument is damaged.